The only reason he can hit it in the demo is because the top guy is postured so far back that the bottom guy's hips are free. Usually you have to cross face them and press their head back to force the space and usually catch them sleeping with their back leg sitting too far back. If they slip their leg out and throw their weight high then get ready to gable, explode your hips, and roll to the opposite side.
The escape from the position is usually aided by having a push and pull option where their counter for one escape baits them into your other escape. But all of this is dangerous to do if you can't get your right elbow below their body and out of danger.